Abstract: An airway structure, a cylinder cover and a Miller-profile engine are provided. The airway structure includes an intake duct and an intake valve arranged on an intake side, and an exhaust duct and an exhaust side roof arranged on an exhaust side. An angle of an axis of an intake valve stem relative to an assembly bottom surface of the cylinder cover is a1; an angle between a revolution cone surface of an intake valve disc and the axis of the intake valve stem is a2, an angle between a plane where the exhaust side roof is located and the assembly bottom surface is a3, a lower guide surface of the intake duct close to an intake throat is inclined downward at an angle of a4 relative to the assembly bottom surface. The airway structure satisfies: a3-3°?a1-a2?a3+3°; and/or, a4-3°?a1-a2?a4+3°.

Abstract: An airway structure, a cylinder cover and a Miller-profile engine are provided. The airway structure includes an intake duct and an intake valve arranged on an intake side, and an exhaust duct and an exhaust side roof arranged on an exhaust side. An angle of an axis of an intake valve stem relative to an assembly bottom surface of the cylinder cover is a1; an angle between a revolution cone surface of an intake valve disc and the axis of the intake valve stem is a2, an angle between a plane where the exhaust side roof is located and the assembly bottom surface is a3, a lower guide surface of the intake duct close to an intake throat is inclined downward at an angle of a4 relative to the assembly bottom surface. The airway structure satisfies: a3?3°?a1-a2?a3+3°; and/or, a4?3°?a1-a2?a4+3°.